Image formation apparatus

ABSTRACT

An image formation apparatus according to an embodiment may include: a print unit that forms an image on a medium; and a medium conveyance unit that conveys the medium to the print unit. The medium conveyance unit may include: a medium guide that is movable in a width direction of the medium perpendicular to a conveyance direction of the medium, to guide a width end of the medium; a guide position detector that detects a position of the medium guide in the width direction of the medium; and a medium end detector that is provided at the medium guide and detects whether there is the medium with the width end guided by the medium guide. The print unit may include a determination unit that determines a set state of the medium based on a detection result by the medium end detector.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority based on 35 USC 119 from prior Japanese Patent Application No. 2018-185644 filed on Sep. 28, 2018, entitled “IMAGE FORMATION APPARATUS, the entire contents of which are incorporated herein by reference.

BACKGROUND

The disclosure relates to an image formation apparatus with a medium guide to be aligned with an end of a medium.

There is a technique of recognizing an irregular sheet size in a printer in such a way that the positions of sheet guides in contact with the left, right, and lower ends of a sheet are detected with a potentiometer (see Japanese Patent Application Publication No. 2000-326613 (Patent Document 1)). Patent Document 1 discloses that, if print data is beyond the range of the recognized sheet size, the image size is adjusted to the sheet size by a scaling factor setting unit to prevent ink from running over roller members such as a press roller.

SUMMARY

In the technique wherein only the positions of the movable sheet guides are detected by the potentiometer in order to detect an irregular sheet size, the sheet size is erroneously recognized when the sheet guides are not completely in contact with the ends of the sheet.

It is desirable to provide an image formation apparatus capable of detecting that a medium has been set correctly in a movable medium guide.

A first aspect of the disclosure is an image formation apparatus that may include: a print unit that forms an image on a medium; and a medium conveyance unit that conveys the medium to the print unit. The medium conveyance unit may include: a medium guide that is movable in a width direction of the medium perpendicular to a conveyance direction of the medium, to guide a width end of the medium; a guide position detector that detects a position of the medium guide in the width direction of the medium; and a medium end detector that is provided at or in the vicinity of the medium guide and detects whether there is the medium with the width end guided by the medium guide. The print unit may include a determination unit that determines a set state of the medium based on a detection result by the medium end detector.

A second aspect of the disclosure is an image formation apparatus that may include: a print unit that forms an image on a medium; and a medium conveyance unit that conveys the medium to the print unit. The medium conveyance unit may include: a plurality of medium guides connected so as to move simultaneously with each other in a width direction of the medium perpendicular to a conveyance direction of the medium, to guide both ends of the medium in the width direction; a guide position detector that detects a position of at least one of the plurality of medium guides; and medium end detectors that are provided at or in the vicinity of the plurality of medium guides and that detect whether there is the medium with the both widthwise ends guided by the plurality of medium guides. The print unit may include a determination unit that determines a set state of the medium based on a detection result by the medium end detectors.

According to the first aspect, it is able to provide the image formation apparatus capable of detecting that the medium has been set correctly in the movable medium guide. According to the second aspect, it is able to provide the image formation apparatus capable of detecting that the medium has been set correctly in the movable medium guides.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a perspective view of a configuration example of an image formation apparatus according to a first embodiment;

FIG. 2 is a diagram illustrating a perspective view of a configuration example when a top cover is opened in the image formation apparatus according to a first embodiment;

FIG. 3 is a diagram illustrating a front view of a configuration example of the image formation apparatus according to a first embodiment as viewed from the roll shaft side;

FIG. 4 is a block diagram illustrating a configuration example of a control system of the image formation apparatus according to a first embodiment;

FIG. 5 is a diagram illustrating a front view of a first example of a state where a sheet is not set correctly in the image formation apparatus according to a first embodiment;

FIG. 6 is a diagram illustrating a front view of a second example of a state where a sheet is not set correctly in the image formation apparatus according to a first embodiment;

FIG. 7A is a flowchart illustrating an example of a control flow of a printing operation in the image formation apparatus according to a first embodiment;

FIG. 7B is a flowchart following FIG. 7A;

FIG. 8 is a diagram illustrating a plan view of a configuration example of a main part in an image formation apparatus according to a second embodiment;

FIG. 9 is a diagram illustrating a side view of a configuration example of the main part in the image formation apparatus according to a second embodiment; and

FIG. 10 is a block diagram illustrating a configuration example of a control system of the image formation apparatus according to a second embodiment.

DETAILED DESCRIPTION

Descriptions are provided hereinbelow for embodiments based on the drawings. In the respective drawings referenced herein, the same constituents are designated by the same reference numerals and duplicate explanation concerning the same constituents is omitted. All of the drawings are provided to illustrate the respective examples only.

The description is given in the following order.

0. Comparative Example 0.1 Problems 1. First Embodiment 1.1 Configuration 1.2 Operation

1.3 Advantageous effects

2. Second Embodiment 2.1 Configuration and Operation 2.2 Advantageous Effects 3. Other Embodiments 0. Comparative Example 0.1 Problems

In the technique as described in Patent Document 1 (Japanese Patent Application Publication No. 2000-326613) wherein only the position of the movable sheet guide is detected by the potentiometer to recognize the sheet size, the sheet size is erroneously recognized when the sheet guide is not completely in contact with the left, right, and lower ends of the sheet. For example, if the sheet guide on the right side is in a position about 10 mm wider than the sheet, a printer recognizes the actual sheet size +10 mm width. Therefore, when the original print size specified by print data is scaled by a scaling factor corresponding to the recognized sheet size, a scaling factor larger than the scaling factor to be actually set is set, which may cause ink to run over a roller member such as a press roller. The ink on the roller member may run out and stains may occur. Then, when printing is carried out by continuously reloading a sheet of +10 mm width aligned with the sheet guide, the ink adhering to the roller member adheres to the back side of the reloaded sheet, resulting in a failure to obtain a satisfactory printed matter.

Therefore, it is desirable to develop a technique capable of detecting that a medium is set correctly in a movable medium guide and reducing false recognition of the size of the medium to be printed.

1. First Embodiment 1.1 Configuration

FIG. 1 is a perspective view illustrating a configuration example of an image formation apparatus according to a first embodiment. FIG. 2 is a perspective view illustrating a configuration example when a top cover 109 to be described later is opened in the image formation apparatus according to a first embodiment. FIG. 3 is a front view illustrating a configuration example of the image formation apparatus according to a first embodiment as viewed from the side of a roll shaft 102 to be described later. FIG. 4 illustrates a configuration example of a control system in the image formation apparatus according to a first embodiment.

As illustrated in FIG. 4, the image formation apparatus according to a first embodiment includes a sheet leading end detection sensor 204, a paper end sensor 205, a guide position detector 208, a sheet left-end sensor 301, a main controller 400, a notification unit 401, and a sheet state determination unit 403. Note that the main controller 400, the notification unit 401, and the sheet state determination unit 403 can be implemented using: a memory as a storage device that stores a control program; and a processor that executes the control program stored in the memory. Otherwise, parts of the main controller 400, the notification unit 401, and the sheet state determination unit 403 may be implemented using a circuit, and the rests of the main controller 400, the notification unit 401, and the sheet state determination unit 403 may be implemented using: a memory as a storage device that stores a control program; and a processor that executes the control program stored in the memory.

The main controller 400 performs overall control of the respective units in the image formation apparatus. The main controller 400 receives print data to generate image data. When receiving a print command, the main controller 400 forms an image based on the generated image data on a medium using a printer unit 110 or a printer device (FIG. 1 and the like) to be described later. Further, the main controller 400 controls the printer unit 110 to convey the medium by a medium conveyance unit 100 to be described later.

The guide position detector 208 can detect the position of a sheet width guide 106 to be described later.

The sheet left-end sensor 301 is provided on the sheet width guide 106 to be described later, and is movable along with the sheet width guide 106. The sheet left-end sensor 301 detects whether there is a medium having its width end guided by the sheet width guide 106. The sheet left-end sensor 301 can detect the end (left end) of the medium corresponding to the position where the sheet width guide 106 is provided.

The sheet state determination unit 403 is a determination unit that determines the set state of the medium based on the detection result of the sheet left-end sensor 301. The sheet state determination unit 403 determines whether or not the medium is set correctly in the sheet width guide 106.

The notification unit 401 includes a display unit 402 or a display. The notification unit 401 notifies the set state of the medium determined by the sheet state determination unit 403. The notification unit 401 displays the set state of the medium, for example, on the display unit 402.

In the image formation apparatus, the sheet width guide 106 corresponds to an example of a “medium guide.” Meanwhile, the guide position detector 208 corresponds to an example of a “guide position detector.” The sheet left-end sensor 301 corresponds to an example of a “medium end detector” or “a medium widthwise end detector.” The sheet state determination unit 403 corresponds to an example of a “determination unit.”

Hereinafter, with reference to FIGS. 1 to 3, description is given of a mechanical configuration example of the image formation apparatus according to a first embodiment, together with the components of the control system illustrated in FIG. 4.

It is assumed, in the image formation apparatus, that a width direction of the medium perpendicular to a conveyance direction of the medium is a left-right direction (X direction in FIG. 1 and the like). In the image formation apparatus, one end (for example, the left end) of the medium corresponds to an example of a “first end.” The other end (for example, the right end) of the medium corresponds to an example of a “second end.”

The image formation apparatus according to a first embodiment includes: the printer unit 110 that forms an image on a medium; and the medium conveyance unit 100 that conveys the medium to the printer unit 110.

The printer unit 110 corresponds to an example of a “print unit.”

FIGS. 1 to 3 illustrate a configuration example where the medium conveyance unit 100 conveys a sheet 101 wound in a roll shape to the printer unit 110 as a medium.

As illustrated in FIG. 1, the medium conveyance unit 100 in the image formation apparatus includes the roll shaft 102, a roll shaft arm 103, a tension bar 104, a sheet conveyance unit 105, the sheet width guide 106, a sheet width guide position adjustment dial 108, and a top cover 109.

As illustrated in FIG. 2, the medium conveyance unit 100 in the image formation apparatus further includes a first sheet feed roller 201, a second sheet feed roller 203, the sheet leading end detection sensor 204, and a sheet cutter 207.

As illustrated in FIG. 3, the medium conveyance unit 100 in the image formation apparatus further includes the sheet left-end sensor 301 and a sheet reference side guide 305.

In the medium conveyance unit 100, the roll shaft 102 that fixes the sheet 101 wound in a roll shape is fixed by the roll shaft arm 103, and the sheet 101 wound in a roll shape is let out while rotating about the roll shaft 102.

The roll shaft 102 has an unillustrated built-in torque limiter so that the sheet 101 is not let out excessively to sag even if force from the sheet feed rollers in the sheet conveyance unit 105 is applied thereto.

The tension bar 104 is disposed between the roll shaft 102 and the sheet conveyance unit 105, and has an effect of suppressing meandering of the sheet 101 or the like by pressing the sheet 101 from above and applying tension thereto.

The sheet reference side guide 305 corresponds to an example of a “fixed guide.”. The sheet reference side guide 305 is provided on the end (right end) side opposite to the end (left end) where the sheet width guide 106 is provided, in the width direction of the sheet 101. The sheet 101 is set abutting on the sheet reference side guide 305 at a sheet reference position 107. Since the sheet reference side guide 305 is fixed to one side (right end), the sheet reference position 107 of the sheet reference side guide 305 is a fixed position. It is detected by the paper end sensor 205 that the sheet 101 is set abutting on the sheet reference side guide 305 at the sheet reference position 107. The sheet 101 is aligned and set by the sheet width guide 106 at the end (left end) opposite to the sheet reference position 107.

The sheet width guide 106 is interlocked with the sheet width guide position adjustment dial 108, and the sheet width guide 106 is moved in the left-right direction by rotating the sheet width guide position adjustment dial 108 clockwise or counterclockwise.

The top cover 109 is configured to cover the sheet feed roller and various sensors in the sheet conveyance unit 105, and is configured to be able to recognize opening/closing by an unillustrated cover open sensor. An unillustrated control board is mounted on the sheet conveyance unit 105 to enable communication with the printer unit 110.

With reference to FIG. 2, description is given of a procedure for opening the top cover 109 and setting the sheet 101 in the sheet conveyance unit 105.

First, an operator or a user sets the sheet 101 in an abutted state all the way back of the roll shaft 102. Meanwhile, the operator moves the position of the sheet width guide 106 by the sheet width guide position adjustment dial 108 so as to be wider than the width of the sheet 101 to be set.

Next, the operator moves the tension bar 104 upward in the tension bar movable direction 206, draws the sheet 101 to pass below the tension bar 104 to reach the first sheet feed roller 201.

The first sheet feed roller 201 is configured such that only the upper roller thereof can move up and down as indicated by the sheet feed roller movable direction 202 by an unillustrated opening lever. The upward arrow in the sheet feed roller movable direction 202 indicates a roller separated state where the upper roller is separated from the lower roller, while the downward arrow in the sheet feed roller movable direction 202 indicates a roller nip state where the upper roller is pressed against the lower roller to nip the sheet 101 therebetween.

When the operator makes the leading end of the sheet 101 pass through the first sheet feed roller 201, the operator draws the sheet to pass the first sheet feed roller after separating the upper roller from the lower roller of the first sheet feed roller 201, and then returns the unillustrated opening lever with the sheet 101 abutting on the sheet reference side guide 305 (FIG. 3) to set the roller nip state, thereby fixing the sheet 101. Next, the operator rotates the sheet width guide position adjustment dial 108 to adjust the position of the sheet width guide 106 to match the width of the set sheet 101.

Finally, the operator closes the top cover 109 and lowers the tension bar 104 to complete the setting of the sheet 101.

The sheet conveyance unit 105 includes an unillustrated motor for rotating the first sheet feed roller 201 and the second sheet feed roller 203, and starts a sheet feed operation of the sheet 101 when the top cover 109 is in the closed state.

The sheet cutter 207 is also provided between the first sheet feed roller 201 and the second sheet feed roller 203 to enable the sheet 101 wound into a roll shape to be cut and discharged. The sheet cutter 207 may be a rotary cutter, or may be a circle cutter, a guillotine cutter, or the like.

The sheet leading end detection sensor 204 is provided on the downstream side of the first sheet feed roller 201. The sheet leading end detection sensor 204 has a function to detect the leading end of the sheet 101 and check the sheet feed state, and also has a function as a unit that determines the cut position of the sheet 101. To be more specific, the cut position can be determined by monitoring how much the first sheet feed roller 201 has moved after the sheet leading end detection sensor 204 detects the presence of the sheet.

The sheet leading end detection sensor 204 is disposed on the sheet reference position 107 side, and detects the right end of the sheet 101 as much as possible. The sheet leading end detection sensor 204 may be configured using an actuator and a transmission photo-interrupter, or may be configured using a reflection sensor, or a separation type transmission photo-interrupter such as one that receives light on the upper side of the sheet 101 and emits light on the lower side thereof.

The paper end sensor 205 or a sheet end sensor detects whether or not the sheet 101 has been set abutting on the sheet reference side guide 305 and whether or not the paper end is reached. The paper end sensor 205 may be referred to as a sheet right-end sensor, a sheet reference side sensor, or a sheet tail end sensor.

As illustrated in FIG. 3, the sheet width guide 106 has a protrusion that covers the left end of the sheet 101 as viewed from the roll shaft 102 side, and the sheet left-end sensor 301 is mounted on the protrusion. However, in the image formation apparatus, the sheet left-end sensor 301 is not limited to a structure in which the left end is covered from above, and a structure may be adopted such that no protrusion is provided and a sensor is provided below the sheet 101.

The sheet left-end sensor 301 may be configured using an actuator and a transmission photo-interrupter, or may be configured using a reflection sensor. Alternatively, the sheet left-end sensor 301 may be configured using, for example, a separation type transmission photo-interrupter with the light reception side corresponding to the front side of the sheet 101 and the light emission side corresponding to the back side thereof.

As illustrated in FIG. 3, the sheet width guide 106 can move a sheet width guidable range 304 from a sheet minimum size 302 to a sheet maximum size 303, for example, in the width direction of the sheet 101. The sheet left-end sensor 301 can also detect the left end of the sheet 101 within the range.

The guide position detector 208 detects, for example, the position in the width direction of the sheet width guide 106 within the sheet width guidable range 304 from the sheet reference position 107. The guide position detector 208 can detect, for example, the position in the width direction of the sheet width guide 106 with respect to the sheet reference position 107. The guide position detector 208 may be, for example, an unillustrated position detection sensor. The position detection sensor may be a volume resistor or a potentiometer.

1.2 Operation

FIG. 5 illustrates a first example of a state where the sheet 101 is not set correctly in the image formation apparatus according to a first embodiment. FIG. 6 illustrates a second example of the state where the sheet 101 is not set correctly therein.

The following two cases are conceivable as the case where the sheet 101 is not set correctly: (1) when the left end of the sheet 101 is separated from the sheet width guide 106 (FIG. 5) and (2) when the right end of the sheet 101 is separated from the sheet reference position 107 (FIG. 6).

FIGS. 7A and 7B illustrate an example of a control flow of a printing operation in the image formation apparatus according to a first embodiment. FIGS. 7A and 7B illustrate an operation example for enabling normal conveyance to be executed by detecting the two cases illustrated in FIGS. 5 and 6.

First, the main controller 400 determines whether or not the paper end sensor 205 detects the sheet 101 (detects the presence of the sheet) (Step S500). When the sheet 101 is not detected by the paper end sensor 205 (Step S500; N), the main controller 400 uses the notification unit 401 to notify an operator of that the sheet 101 is not detected (there is no sheet) (Step S500A).

When the sheet 101 is detected (the presence of the sheet is detected) by the paper end sensor 205 (Step S500; Y), the main controller 400 then determines whether or not the sheet 101 is detected (the presence of the sheet is detected) by the sheet left-end sensor 301 (Step S501). When the sheet 101 is not detected by the sheet left-end sensor 301 (Step S501; N), the above case (1) (FIG. 5) is assumed. In this case, the sheet state determination unit 403 determines that there is an error in setting the sheet 101. In this case, the main controller 400 stops the conveyance of the sheet 101 (Step S502). The main controller 400 also causes the notification unit 401 to notify the operator of the error in setting the sheet 101 (Step S502), and urges resetting of the sheet 101.

When the sheet 101 is detected (the presence of the sheet is detected) by the sheet left-end sensor 301 (Step S501; Y), the main controller 400 sets the respective units in a printing standby state (Step S503).

Then, the main controller 400 determines whether or not there is a print command (whether or not the print command is received) (Step S504), and waits until there is a print command (until the print command is received) (Step S504; N).

If the print command is received (Step S504; Y), the main controller 400 determines whether or not the position of the sheet width guide 106 matches the print data size (Step S505). When determining that the position of the sheet width guide 106 matches the print data size (Step S505; Y), the main controller 400 directly starts the printing operation (Step S508).

When determining that the position of the sheet width guide 106 does not match the print data size (Step S505; N), the main controller 400 then determines whether or not the print data width is wider than the position of the sheet width guide 106 (Step S506). When determining that the print data width is not wider (the print data width is narrower) than the position of the sheet width guide 106 (Step S506; N), the main controller 400 directly starts the printing operation since the print data fits within the sheet width (Step S508).

When determining that the print data width is wider (Step S506; Y), the printer unit 110 processes and corrects the print data according to the sheet width (Step S507). For processing and correction of the print data, the original print size may be reduced at an appropriate scaling factor, for example, or the print data that runs over the left end of the sheet may be cut off.

When the printing operation is started (Step S508), the sheet state determination unit 403 then determines whether or not the sheet leading end detection sensor 204 detects the sheet 101 (detects the presence of the sheet) (Step S509). When the sheet 101 is not detected by the sheet leading end detection sensor 204 (Step S509; N), the case (2) described above (FIG. 6) is assumed. In this case, the main controller 400 stops the conveyance of the sheet 101 (Step S510). The main controller 400 also causes the notification unit 401 to notify the operator of the error in setting the sheet 101 (Step S510), and urges resetting of the sheet 101.

When the sheet 101 is detected (the presence of the sheet is detected) by the sheet leading end detection sensor 204 (Step S509; Y), the main controller 400 continues the conveyance of the sheet 101. Next, the main controller 400 determines whether or not the paper end sensor 205 detects a paper end (detects no sheet) (Step S511). When the paper end is detected by the paper end sensor 205 (step S511; Y), the main controller 400 stops the conveyance of the sheet 101 (Step S512). Further, the notification unit 401 notifies the operator of the paper end (Step S512).

When the paper end is not detected by the paper end sensor 205 (Step S511; N), the main controller 400 then determines whether or not the print data ends (Step S513). When determining that the print data does not end (Step S513; N), the processing returns to Step S511 to continue printing until the print data ends.

When determining that the print data ends (Step S513; Y), the main controller 400 causes the sheet cutter 207 to cut the rear end of the sheet 101 (Step S514) and discharges the sheet 101. Thus, the printing operation is completed.

1.3 Advantageous Effects

As described above, the image formation apparatus according to a first embodiment includes the guide position detector 208 capable of detecting the position of the sheet width guide 106, the sheet left-end sensor 301 that is provided on the sheet width guide 106 and detects whether there is a sheet 101 having its width end guided by the sheet width guide 106, and the sheet state determination unit 403 that determines the set state of the sheet 101 based on the detection result by the sheet left-end sensor 301. Thus, it can be detected that the sheet 101 is set correctly in the sheet width guide 106. As a result, false recognition of the size of the sheet 101 can be reduced.

The image formation apparatus according to a first embodiment enables a configuration in which printing is not started until the width of the sheet 101 used always matches the position of the sheet width guide 106, since the sheet left-end detection sensor 301 is provided on the sheet width guide 106 capable of position detection. This makes it possible to prevent a problem that occurs when print data runs over the sheet 101, for example, adhesion of unfixed toner, ink, and the like to the conveyance member in the printer unit 110. The effect of reducing skewing of the sheet 101 with respect to the conveyance direction, which is the intended purpose of the sheet width guide 106, can also be expected. Therefore, the image formation apparatus according to a first embodiment can prevent problems such as ink running over due to false recognition of the size of the sheet 101 and the occurrence of skewing caused by the sheet width guide 106 separated from the end of the sheet 101.

2. Second Embodiment

Next, description is given of an image formation apparatus according to a second embodiment. Note that, in the following, substantially the same constituent components as those of the image formation apparatus according to a first embodiment described above are denoted by the same reference numerals, and description thereof is omitted as appropriate.

2.1 Configuration and Operation

FIG. 8 is a plan view illustrating a configuration example of a main part of the image formation apparatus according to a second embodiment. FIG. 9 is a side view illustrating a configuration example of the main part of the image formation apparatus according to a second embodiment. FIG. 10 illustrates a configuration example of a control system of the image formation apparatus according to a second embodiment.

As illustrated in FIG. 10, the image formation apparatus according to a second embodiment includes a main controller 500, a notification unit 501, a sheet state determination unit 503, an upper-end guide position detector 504, a left-end guide position detector 505, and reflection sensors 607A, 607B, 607C, and 607D.

The main controller 500 performs overall control of the respective units in the image formation apparatus. The main controller 500 receives print data to generate image data. When receiving a print command, the main controller 500 forms an image based on the generated image data on a medium using a printer unit 110 (FIG. 1 and the like). Further, the main controller 500 controls the printer unit 110 to convey the medium by a medium conveyance unit 100A to be described later.

The left-end guide position detector 505 can detect the position in the width direction of a sheet left-end guide 605 to be described later. The upper-end guide position detector 504 can detect the position of a sheet upper-end guide 604 to be described later in the conveyance direction.

The reflection sensor 607A is provided on the sheet left-end guide 605 to be described later, is movable along with the sheet left-end guide 605, and can detect the left end of the medium. The reflection sensor 607B is provided on a sheet right-end guide 606 to be described later, is movable along with the sheet right-end guide 606, and can detect the right end of the medium. The reflection sensor 607C is provided on the sheet upper-end guide 604 to be described later, is movable along with the sheet upper-end guide 604, and can detect the upper end of the medium. The reflection sensor 607D is provided on a sheet tray lower end 611 as a fourth medium guide to be described later, and can detect the lower end of the medium.

The sheet state determination unit 503 is a determination unit that determines the set state of the medium based on at least the detection results from the reflection sensors 607A and 607B.

The notification unit 501 includes a display unit 502. The notification unit 501 notifies the set state of the medium determined by the sheet state determination unit 503. The notification unit 501 displays the set state of the medium on the display unit 502, for example.

In the image formation apparatus according to a second embodiment, at least the reflection sensors 607A and 607B correspond to examples of “medium end detectors” or “medium widthwise end detectors.”

In the image formation apparatus according to a second embodiment, at least the sheet left-end guide 605 and the sheet right-end guide 606 each correspond to a specific example of a “medium guide.”

In the image formation apparatus according to a second embodiment, at least the left-end guide position detector 505 corresponds to a specific example of a “guide position detector.”

Hereinafter, with reference to FIGS. 8 and 9, description is given of a mechanical configuration example of the image formation apparatus according to a second embodiment, together with the constituent components of the control system illustrated in FIG. 10.

As for the image formation apparatus according to a first embodiment, the description is given of the case where the sheet reference position 107 in the sheet reference side guide 305 is fixed to one side (right end). As for the image formation apparatus according to a second embodiment, on the other hand, description is given of the case where the paper reference position is the center of the sheet.

It is assumed, in the image formation apparatus according to a second embodiment, that a width direction perpendicular to a conveyance direction of the medium is a left-right direction (X direction in FIG. 8 and the like).

The image formation apparatus according to a second embodiment includes a printer unit 110 substantially the same as that in the image formation apparatus according to a first embodiment. The image formation apparatus according to a second embodiment also includes the medium conveyance unit 100A that conveys a medium to the printer unit 110. The image formation apparatus according to a second embodiment is different from the image formation apparatus according to a first embodiment in the structure of the medium conveyance unit 100A.

FIGS. 8 and 9 illustrate a configuration example where the medium conveyance unit 100A conveys a sheet 603 cut into a square shape to the printer unit 110 as a medium.

As illustrated in FIG. 8, the image formation apparatus according to a second embodiment includes, as the medium conveyance unit 100A, a sheet tray 601, a pickup roller 602, the sheet upper-end guide 604, the sheet left-end guide 605, the sheet right-end guide 606, the reflection sensors 607A to 607D, and a gear 609.

The sheet 603 is stored in the sheet tray 601. In the sheet tray 601, the sheet upper-end guide 604, the sheet left-end guide 605, and the sheet right-end guide 606 are provided to guide the respective ends of the sheet 603.

The sheet tray lower end 611 is configured to serve as a sheet lower-end guide that guides the lower end of the sheet 603.

The pickup roller 602 is located in a position corresponding to the lower end of the sheet 603 in the sheet tray 601. When conveyance of the sheet 603 is started, the pickup roller 602 is rotated to enable the sheet 603 to be conveyed to the printer unit 110 (FIG. 1) one by one.

The left-end guide position detector 505 can detect the position in the width direction of the sheet left-end guide 605 within a sheet left-end guide position detection range 608. As in the case of the guide position detector 208 in a first embodiment, the left-end guide position detector 505 may be, for example, an unillustrated position detection sensor. The position detection sensor may be a volume resistor or a potentiometer.

The sheet right-end guide 606 is connected to the sheet left-end guide 605, and is movable in the left-right direction in conjunction with the sheet left-end guide 605. For example, the sheet left-end guide 605 and the sheet right-end guide 606 are connected by the gear 609, and are configured to operate symmetrically about the gear 609. Therefore, the position of the sheet right-end guide 606 in the width direction can also be known by detecting only the position of the sheet left-end guide 605 in the width direction with the left-end guide position detector 505. Accordingly, the width of the sheet 603 in the left-right direction can be detected.

The upper-end guide position detector 504 can detect the position of the sheet upper-end guide 604 in the conveyance direction within a sheet upper-end guide position detection range 610. As in the case of the guide position detector 208 in a first embodiment, the upper-end guide position detector 504 may be, for example, an unillustrated position detection sensor. The position detection sensor may be a volume resistor or a potentiometer.

The reflection sensor 607A is provided, for example, immediately below the sheet left-end guide 605. The reflection sensor 607B is provided, for example, immediately below the sheet right-end guide 606. The reflection sensor 607C is provided, for example, immediately below the sheet upper-end guide 604.

The reflection sensor 607D is provided, for example, immediately below the pickup roller 602 at the sheet tray lower end 611.

With the above configuration, the position of each sheet guide can be matched with the size of the sheet 603. Also, the size of the set sheet 603 can be detected.

The sheet state determination unit 503 determines that the sheet 603 is in a normal state when “sheet present” is detected at all the upper, lower, left, and right ends of the sheet 603, for example, by the reflection sensors 607A to 607D, respectively.

For example, when any one of the reflection sensors 607A to 607D detects “sheet out”, the sheet state determination unit 503 determines that the sheet 603 is not set correctly. In this case, the main controller 500 may not start printing.

2.3 Advantageous Effects

As described above, the image formation apparatus according to a second embodiment makes it possible to recognize the size of a medium (cut sheet) whose sheet reference position is at the center of the sheet, compared with the image formation apparatus according to a first embodiment.

Other configurations, operations, and advantageous effects may be substantially the same as those of the image formation apparatus according to a first embodiment described above.

3. Other Embodiments

The invention is not limited to the description of the above embodiments, and various modifications can be made thereto.

For example, although the description is given of the case of the single-function image formation apparatus as an example in each of the above embodiments, the image formation apparatus may be a multifunction printer (MFP) including copy, scan, print, and fax functions and the like.

The above embodiments are to be considered in all respects as illustrative, and not restrictive. The scope of the invention is indicated by the appended claims rather than by the foregoing description. Hence, all configurations including the meaning and range within equivalent arrangements of the claims are intended to be embraced in the invention. 

1. An image formation apparatus comprising: a print unit that forms an image on a medium; and a medium conveyance unit that conveys the medium to the print unit, wherein the medium conveyance unit includes a medium guide that is movable in a width direction of the medium perpendicular to a conveyance direction of the medium, to guide a width end of the medium, a guide position detector that detects a position of the medium guide in the width direction of the medium, and a medium end detector that is provided at or in the vicinity of the medium guide and detects whether there is the medium with the width end guided by the medium guide, and the print unit includes a determination unit that determines a set state of the medium based on a detection result by the medium end detector.
 2. The image formation apparatus according to claim 1, further comprising: a notification unit that makes a notification of the set state of the medium determined by the determination unit.
 3. The image formation apparatus according to claim 2, wherein the notification unit includes a display unit that displays the set state of the medium determined by the determination unit.
 4. The image formation apparatus according to claim 1, wherein the determination unit determines whether or not the medium is set correctly in the medium guide.
 5. The image formation apparatus according to claim 1, wherein the medium guide is provided at a first end side of the medium in the width direction, and a fixed guide to be a reference position of the medium is provided at a second end side opposite to the first end side of the medium in the width direction.
 6. An image formation apparatus comprising: a print unit that forms an image on a medium; and a medium conveyance unit that conveys the medium to the print unit, wherein the medium conveyance unit includes a plurality of medium guides connected so as to move simultaneously with each other in a width direction of the medium perpendicular to a conveyance direction of the medium, to guide both ends of the medium in the width direction, a guide position detector that detects a position of at least one of the plurality of medium guides, and medium end detectors that are provided at or in the vicinity of the plurality of medium guides and that detect whether there is the medium with the both ends guided by the plurality of medium guides, and the print unit includes a determination unit that determines a set state of the medium based on a detection result by the medium end detectors. 